Play Summon: Leviathan to bounce all of our opponent's creatures and smash for a ton of damage
On attack, it forces an opponent to sacrifice a creature, and if they do, you get a 2/2 Zombie token for your trouble
Even if your opponents hand is empty, you still get to draw a card instead of making them discard to make sure the advantage bar stays on your side
If they dont try to ramp their lands or simply get a slow start, this card might sit in your hand gathering dust, or you might have to play it to free up space in your hand before it can be used in response to a ramp effect or fetchland
After that you will get to see your stats
And while this can be expanded out to cover a wide variety of interactions between similarly sized creatures, those aren't the only kinds of trades that happen